Solid-state image pickup device and image pickup system

Abstract

The present invention relates to a solid-state image pickup device. The device includes a first substrate including a photoelectric conversion element and a transfer gate electrode configured to transfer charge from the photoelectric conversion element, a second substrate having a peripheral circuit portion including a circuit configured to read a signal based charge generated in the photoelectric conversion element, the first and second substrates being laminated. The device further includes a multilayer interconnect structure, disposed on the first substrate, including an aluminum interconnect and a multilayer interconnect structure, disposed on the second substrate, including a copper interconnect.

The invention claimed is: 
     
       1. A solid-state image pickup device comprising:
 a first substrate having a first transistor and a photoelectric conversion element; 
 a second substrate having a second transistor, the first and second substrates being laminated; 
 a first interconnect electrically connected to the second transistor, the first interconnect being mainly made of copper; 
 a second interconnect electrically connected to the first interconnect, the second interconnect being mainly made of copper; 
 a third interconnect electrically connected to the second interconnect and disposed between the first substrate and the second substrate, the third interconnect being mainly made of aluminum; and 
 a plug arranged in a hole of an insulating interlayer between the first substrate and the second substrate, the plug being made of tungsten, 
 wherein
 a distance between the second interconnect and the second substrate is greater than a distance between the first interconnect and the second substrate, 
 a distance between the second interconnect and the first substrate is greater than a distance between the third interconnect and the first substrate, 
 the distance between the third interconnect and the first substrate is greater than a distance between a gate electrode of the first transistor and the first substrate, and 
 the distance between the third interconnect and the first substrate is greater than a distance between the plug and the first substrate. 
 
 
     
     
       2. The device according to  claim 1 , wherein the first substrate and second substrate are laminated such that the first interconnect and the second interconnect are disposed between the first substrate and the second substrate. 
     
     
       3. The device according to  claim 1 , wherein the third interconnect is electrically connected to the first transistor. 
     
     
       4. The device according to  claim 1 , wherein the first interconnect is electrically connected to the second transistor through another plug disposed between the second substrate and the first interconnect, the another plug being made of tungsten. 
     
     
       5. The device according to  claim 1 , wherein the second transistor includes a metal compound disposed in contact with an insulating interlayer. 
     
     
       6. The device according to  claim 1 , wherein the insulating interlayer is disposed between the third interconnect and the first substrate. 
     
     
       7. The device according to  claim 1 , wherein a fourth interconnect electrically connected to the first transistor through the plug is disposed between the first substrate and the second substrate, and the distance between the third interconnect and the first substrate is greater than a distance between the fourth interconnect and the first substrate. 
     
     
       8. The device according to  claim 1 , wherein an antidiffusion film for copper is disposed between the first interconnect and the second interconnect. 
     
     
       9. The device according to  claim 8 , wherein the antidiffusion film for copper is patterned so as to correspond to a pattern of the first interconnect. 
     
     
       10. The device according to  claim 4 , wherein the second transistor includes a metal compound connected to the another plug. 
     
     
       11. The device according to  claim 1 , wherein the first transistor is a transfer transistor to transfer charge from the photoelectric conversion element to a floating diffusion. 
     
     
       12. The device according to  claim 1 , wherein the first substrate has an amplifying transistor including a gate electrode to which a signal based on a charge generated in the photoelectric conversion element, is input. 
     
     
       13. An image pickup system comprising:
 a solid-state image pickup device; and 
 a signal processing unit configured to process a signal output from the solid-state image pickup device, wherein 
 the solid-state image pickup device comprises:
 a first substrate having a first transistor and a photoelectric conversion element; 
 a second substrate having a second transistor, the first and second substrates being laminated; 
 a first interconnect electrically connected to the first transistor, the first interconnect being mainly made of copper; 
 a second interconnect electrically connected to the first interconnect, the second interconnect being mainly made of copper; 
 a third interconnect electrically connected to the second interconnect and disposed between the first substrate and the second substrate, the third interconnect being mainly made of aluminum; and 
 a plug arranged in a hole of an insulating interlayer between the first substrate and the second substrate, the plug being made of tungsten, 
 wherein 
 a distance between the second interconnect and the second substrate is greater than a distance between the first interconnect and the second substrate, 
 a distance between the second interconnect and the first substrate is greater than a distance between the third interconnect and the first substrate, 
 the distance between the third interconnect and the first substrate is greater than a distance between a gate electrode of the first transistor and the first substrate, and 
 the distance between the third interconnect and the first substrate is greater than a distance between the plug and the first substrate. 
 
 
     
     
       14. The device according to  claim 7 , wherein the fourth interconnect is electrically connected to the first transistor through a plug disposed between the first substrate and the fourth interconnect, the plug being made of tungsten. 
     
     
       15. The device according to  claim 7 , wherein an interconnect included in an interconnect layer including the fourth interconnect, is electrically connected to the gate electrode of the first transistor. 
     
     
       16. A solid-state image pickup device comprising:
 a first substrate having a photoelectric conversion element and a first transistor; 
 a second substrate having a second transistor, the first and second substrates being laminated; 
 a first interconnect electrically connected to the second transistor; 
 a second interconnect electrically connected to the first interconnect, the second interconnect being mainly made of copper; 
 a third interconnect electrically connected to the second interconnect, the third interconnect being mainly made of aluminum; and 
 a fourth interconnect electrically connected to the third interconnect, 
 wherein 
 a distance between the second interconnect and the second substrate is greater than a distance between the first interconnect and the second substrate, 
 a distance between the second interconnect and the first substrate is greater than a distance between the third interconnect and the first substrate, 
 the distance between the third interconnect and the first substrate is greater than a distance between the fourth interconnect and the first substrate, and 
 the distance between the fourth interconnect and the first substrate is greater than a distance between a gate electrode of the first transistor and the first substrate. 
 
     
     
       17. The device according to  claim 16 , wherein the first interconnect, the second interconnect, the third interconnect and the fourth interconnect are disposed between the first substrate and the second substrate. 
     
     
       18. The device according to  claim 16 , wherein the first substrate and the fourth interconnect are electrically connected each other through a plug disposed between the fourth interconnect and the first substrate, the plug being made of tungsten. 
     
     
       19. The device according to  claim 16 , wherein the second substrate and the first interconnect are electrically connected each other through a plug disposed between the second substrate and the first interconnect, the plug being made of tungsten.